• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.06a
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• pp.1613-1616
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• 2005

In this paper, we developed an algorithm of generating cam contour curve for hinge mechanism of folder-type mobile phone. The main feature of this hinge mechanism is that we can operate uniform torque to open or close the mobile phone. We divided the opening or closing intervals of the cam into finite sub-intervals, and then we determined the cam contour curve of each sub-interval as a parabolic curve. Finally, these finite parabolic curves form the total cam contour. We can design single cam, which composed moving cam with contour curve and fixed cam that plays only roller, and twin cam with contour curve that is made up the pair of two cams symmetrically.

• Journal of the Korean Society for Precision Engineering
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• v.19 no.11
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• pp.83-88
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• 2002

In order to predict the moldability of a injection molded part, a simulation of filling is needed. Short shot is one of the most frequent troubles encountered during injection molding process. The adjustment of process conditions is the most economic way to troubleshoot the problematic short shot in cost and time since the mold doesn't need to be modified at all. But it is difficult to adjust the process conditions appropriately in no times since it requires an empirical knowledge of injection molding. In this paper, the intelligent CAE system synergistically combines fuzzy-neural network (FNN) for heuristic knowledge with CAE programs for analytical knowledge. To evaluate the intelligent algorithms, a cellular phone flip has been chosen as a finite element model and filling analyses have been performed with a commercial CAE software. As the results, the intelligent CAE system drastically reduces the troubleshooting time of short shot in comparison with the experts' conventional methodology which is similar to the golden section search algorithm.

• Journal of the Korean Society for Precision Engineering
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• v.14 no.4
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• pp.72-77
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• 1997

In the temperature analysis of hot metal forming process, the heat transfer conditions between the work-piece and the tool have improtant influences upon the temperature distribution. The accuracy of thermal analysis depends on the proper description of boundary conditions including heat transfer. At the contact surface of two materials with different temperatures, this requires the knowledge of the overall heat transfer coefficient. In order to determine the overall heat transfer coefficient, a technique is developed. The technique involves temperature measurement by using thermocouples during hot upsetting operations and finite element computation. The overall heat transfer coefficient is determined using a non-linear optimization technique.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.24 no.10
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• pp.1335-1342
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• 2000

Three-dimensional flow analysis and numerical optimization methods are presented for the design of an axial-flow fan. Steady, incompressible, three-dimensional Reynolds-averaged Navier-Stokes equations are used as governing equations, and standard k- ${\varepsilon}$ turbulence model is chosen as a turbulence model. Governing equations are discretized using finite volume method. Steepest descent method, conjugate gradient method and BFGS method are compared to determine the searching directions. Golden section method and quadratic fit-sectioning method are tested for one dimensional search. Objective function is defined as a ratio of generation rate of the turbulent kinetic energy to pressure head. Two variables concerning sweep angle distribution are selected as the design variables. Performance of the final fan designed by the optimization was tested experimentally.

• Magazine of the Korean Society of Agricultural Engineers
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• v.32 no.3
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• pp.47-55
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• 1990

An adaptive algorithm was applied to forecast daily stream flows in real time using rainfall data. A three-component tank model was selected to simulate the flows and its time-variant parameters were self-calibrated with updated data using a parameter optimization scheme, golden section search method. The resulting adaptive model, APTANK, was applied to six watersheds, ranging from 0.47 to 33.62 km$^2$ size and the simulated daily streamflows were compared with the measured. The simulation results were in good agreement with the field data. APTANK is found to be applied to real-time flow simulation purposes such as a tool for irrigation water resources management and operations. The model is particularly good to simulate streamflows on dry days as compared to wet days having runoff-induced precipitation.

• Proceedings of the Korea Concrete Institute Conference
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• 2000.10a
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• pp.253-258
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• 2000

Recently, the area of design optimization, especially structural optimization, has been and to be a continuous active area of research. And the design optimizations of port facilities have been achieved by many other civil engineers. But the design optimization of port facilities were limited to the design optimization of the breasting dolphin. This paper invested the design optimization of mooring pier and the foundations of mooring pier was suggested considering the convenience of repair and reinforcement work. The mooring pier devised with prestressed precast concrete panel and rigid frame welded wide flange beam to steel pipe pile. To accomplish the design optimization of mooring pier, the Augmented Lagrangian Multiplier Method(ALM) of ADS(Garret N. Vanderplaats) optimization routine, BFGS method as optimizer and Golden Section Method as one dimensional search were utilized. As a result, thirty percent of material cost for construction was reduced by design optimization. The tensile stress of concrete panel and bottom flage was critical constraints under service load. So, using high strength concrete and steel will be economical. And lots of initial values must be invested to accomplish the design optimization in design procedures.

• Proceedings of the KSME Conference
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• 2000.11b
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• pp.304-308
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• 2000

This paper presents a numerical optimization method to design geometric shape of streamwise periodic ribs mounted on one of the principal walls to enhance turbulent heat transfer in a rectangular channel flow. The golden section method is used for the one dimensional search. The optimization is based on Wavier-Stokes analysis of turbulent forced convection with $k-{\varepsilon}$ turbulence model. The width-to-height ratio of a rib is chosen as a design variable. The object function is defined as an inverse of average Nusselt number. An optimum shape of the rib has been obtained with reasonable computing time.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.11 no.1
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• pp.68-75
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• 2012

In this study, the optimal synthesis of planar steering mechanisms for vehicles is studied. The author minimized the steering error between two front wheels subject to the constraints of transmission angles. Nonlinear programming methods such as BFGS method and golden section search method are used for this optimization. As numerical examples, Ackermann's steering mechanism, 6-link and 10-link planar mechanism are adopted to check the usefulness of this method. Consequently, among the three optimized mechanisms, 10-link planar one conducts far more accurate performance subject to tight constraints of transmission angles.

• Steel and Composite Structures
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• v.7 no.3
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• pp.253-262
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• 2007

A methodology to design symmetrically laminated fibre-reinforced structures under transverse loads for minimum weight, with manufacturing uncertainty in the ply angle, is described. The ply angle and the ply thickness are the design variables, and the Tsai-Wu failure criteria is the design constraint implemented. It is assumed that the probability of any tolerance value occurring within the tolerance band, compared with any other, is equal, and thus the approach is a worst-case scenario approach. The finite element method, based on Mindlin plate and shell theory, is implemented, and thus effects like bending-twisting coupling are accounted for. The Golden Section method is used as the search algorithm, but the methodology is flexible enough to allow any appropriate finite element formulation, search algorithm and failure criterion to be substituted. In order to demonstrate the procedure, laminated plates with varying aspect ratios and boundary conditions are optimally designed and compared.

• Journal for History of Mathematics
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• v.13 no.2
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• pp.49-64
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• 2000

Every real number can be expressed as a simple continued fraction. In particular, a number is rational if and only if its simple continued fraction has a finite number of terms. Owing to this property, continued fractions have been a powerful tool which determines a real number to be rational or not. Continued fractions provide not only a series of best estimate for a real number, but also a useful method for finding near commensurabilities between events with different periods. In this paper, we investigate the history and some properties of continued fractions, and then consider their applications in several examples. Also we explain why the Fibonacci numbers and the Golden section appear in nature in terms of continued fractions, with some examples such as the arrangements of petals round a flower, leaves round branches and seeds on seed head.